JP4396958B2 - Pneumatic tire - Google Patents

Description

【００４０】
表１から明らかなように、本発明のタイヤは、従来の比較例タイヤと比べて５０％摩耗時点及び７５％摩耗時点共に耐スリップ性能が優れていることが分かる。
【００４１】
【発明の効果】
本発明は、以上の通りであるので、タイヤ周方向に直線状に延びる縦溝を有する空気入りタイヤにおいて、トレッド面にサイプを多用或いは使用することなく、摩耗初期から末期に至るまで、制動性能及び駆動性能を維持し、かつ上記縦溝側の陸部表面に発生する偏摩耗を防止することができる。
【図面の簡単な説明】
【図１】本発明に係る空気入りタイヤの一実施形態を示す概略トレッド展開図である。
【図２】同タイヤにおける要部拡大概略斜視図である。
【図３】同タイヤにおいて、摩耗したトレッド表面の状態を示す要部拡大概略斜視図である。
【図４】本発明に係る空気入りタイヤの他実施形態を示す概略トレッド展開図である。
【図５】従来技術に係る空気入りタイヤの要部拡大概略斜視図である。
【符号の説明】
１ タイヤトレッド
１ａ トレッド表面
２ 縦溝
３ 陸部
４ａ 接地端
４ｂ 接地端
ＴＣ タイヤ赤道線
ＣＤ タイヤ周方向
Ｐ ジグザグのピッチ長
５ 側壁部
６ 溝底
７ 波形部
８ 折れ曲り部分
ａ_１ 頂辺
ａ_２ 第１の外辺
ａ_３ 底辺
ａ_４ 内辺
Ａ 壁面
Ｂ 壁面
Ｂ_１ 第１斜面
Ｂ_２ 第２斜面
ｂ_１ 頂辺
ｂ₂ 第２の外辺
ｂ_３ 底辺
ＩＰ 交点
ＣＰ_１ 屈曲点
ＣＰ_２ 屈曲点
１０ 陸部
１１ 陸部
１２ タイヤトレッド
１５ 側壁部
１６ 溝底
１７ 波形部
Ｆ 壁面
Ｇ 壁面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic tire having straight longitudinal grooves, and particularly maintains the braking performance and driving performance of the rib-like land portion or the block-like land portion from the beginning to the end of wear of the tread surface. The present invention relates to a pneumatic tire that can prevent uneven wear that occurs on the longitudinal groove side surface of a portion.
[0002]
[Prior art]
Since recent truck / bus tires generally have a long life and low maintenance, it is particularly important to reduce uneven wear on the tread surface among tire performances. Therefore, as a recent trend, the tread pattern of truck / bus tires has progressed in the direction of straightening the longitudinal grooves.
[0003]
[Problems to be solved by the invention]
However, tires constructed with a tread pattern with straight flutes will have reduced braking and drive performance as the tread surface wears, so in order to maintain such performance, sipe must be used frequently on land. I had to.
[0004]
On the other hand, if the sipe is frequently used, a large number of sipe forming blades must be mounted on the tire vulcanization mold, which is difficult to process and affects the manufacturing cost. In addition, when sipe is frequently used, rubber chipping or cutting may occur on the tire surface or rubber filling failure may occur during the vulcanization molding process of the tire. In addition, such tires may cause tread rubber chipping, cracks, and the like during running, and sometimes the sipe itself may cause uneven wear.
[0005]
An object of the present invention is to maintain a braking performance and a driving performance from the beginning to the end of wear in a pneumatic tire having a longitudinal groove extending linearly in a tire circumferential direction without using or using a sipe on a tread surface. In addition, the present invention provides a pneumatic tire capable of preventing uneven wear occurring on the surface of the land portion on the vertical groove side.
[0006]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present invention provides:
The tire tread surface is intermittently arranged by a plurality of vertical grooves extending linearly in the tire circumferential direction, and a rib-like land portion continuously connected along the vertical grooves or a plurality of horizontal grooves along the vertical grooves. In a pneumatic tire having a block-shaped land portion that
The zigzag is repeated along the tire circumferential direction from the tread surface toward the groove bottom direction along the tire circumferential direction on the side wall portion on the vertical groove side in the land portion, and the pitch length of the zigzag is 3 to 8% of the tread width. Is provided with a waveform section,
The corrugated portion is inclined in the direction of narrowing the groove width of the vertical groove from the apexes a ₁ and b ₁ located on both sides of the bent portion recessed toward the land portion on the tread surface. Wall surface A and wall surface B
Wall A is
The top side a _{1 of the} tread surface;
A first outer side a ₂ protruding to the longitudinal groove side;
The bottom side a ₃ on the groove bottom side;
Inner side a _{4 of the} bent portion on the land side
One slope composed of four sides,
The wall surface B has the following first slope B ₁ and second slope B ₂ ,
The first slope _{B 1} is,
The top side b _{1 of the} tread surface,
The first outer side a ₂ in common with the slope A;
And, the second outer side b ₂ connecting the intersection point IP where the first outer side a ₂ intersects the groove bottom and the bending point CP ₁ of the bent portion on the tread surface.
It consists of three sides
The second slope _{B 2} is,
The second outer side b ₂ ,
The inner side a _{4 of} the bent portion,
And the bottom side b ₃ between the bend point CP ₂ on the groove bottom side of the inner side a ₄ and the intersection point IP at which the first outer side a ₂ crosses the groove bottom.
It consists of three sides
Inflection point CP ₂ of bent portions of the groove bottom side, wherein the first perimeter a ₂ is parallel to the top edge b ₁ along the groove bottom from the intersection IP intersecting the groove bottom straight line that intersects the wall surface A Pneumatic tires located on the land side of C are used.
[0007]
Since the tire of the present invention is as described above, braking performance and driving performance are exhibited at the beginning of wear of the tread surface, and at the same time, the zigzag pitch length of the corrugated portion is 3 to 8% of the tread width. The zigzag pattern is a multi-pitch zigzag pattern, and the zigzag of the corrugated portion appearing on the tread surface is repeated mainly on the first slope of the wall surface A and wall surface B, so the degree of zigzag is small. Therefore, in the initial stage of wear, the tire according to the present invention has a configuration that makes the best use of the characteristics of the straight vertical grooves as much as possible, and effectively prevents uneven wear that occurs on the side wall of the land portion on the vertical groove side. can do.
[0008]
Moreover, in the tire according to the present invention, as the wear progresses, the zigzag of the corrugated portion has a second slope of the wall surface B in addition to the wall surface A and the first slope constituting the wall surface B, As the wear progresses, in addition to the edge constituted by the wall A and the first slope of the wall B, the second edge constituted by the first slope and the second slope of the wall B gradually appears. Since the intersection point CP _{2 of} the inner side a _{4 with} the groove bottom is on the land side of the intersection point C of the wall A with a straight line passing through the point IP parallel to the apex b ₁ , the zigzag appearing on the wear surface is large. It becomes. Therefore, at the end of wear, the zigzag degree of the corrugated portion formed by the wall surface A and the first and second slopes of the wall surface B can be set to be repeated in a maximum or near maximum state.
[0009]
The tire of the present invention has a structure in which the braking performance and the driving performance are progressively increased according to the appearance state of the second slope of the wall surface B as the wear progresses, and therefore the traction through the entire process of the tread surface wear. Performance, that is, a decrease in braking performance and driving performance can be suppressed, and the same performance can be maintained.
[0010]
In the present invention, “the degree of zigzag” indicates the total length of the top of the corrugated part constituting the zigzag or the top of the corrugated part after wear, and “the degree of zigzag is large” This indicates that the total length of the top of the corrugated portion constituting the unit is long, that is, the difference between the peaks and troughs of the zigzag corrugated portion, and the entry / exit is large.
[0011]
By the way, a tire having a land portion divided along a longitudinal groove extending in the tire circumferential direction causes shear deformation in a tread including the land portion based on a vertical load received from a road surface at the time of ground contact. It is well known that deformation causes slippage on the tread surface. The slip promotes uneven wear such as so-called river wear by promoting the slip on the tread surface in the width direction end of the land portion with respect to the circumferential force such as the driving force and braking force of the tire.
[0012]
In the tire of the present invention, the zigzag of the corrugated wall surface A and the wall surface B having a so-called multi-pitch narrows the groove width of the vertical groove from the top sides a ₁ and b _{1 of the} tread surface toward the groove bottom. In addition, the zigzag along the tire circumferential direction increases strongly toward the groove bottom due to the appearance of the second inclined surface of the groove wall B along with the wear of the tread surface, and the notch into the groove wall increases.
[0013]
Therefore, in the tire of the present invention, the shear deformation based on the vertical load received at the time of ground contact can be relatively larger on the groove bottom side than the tread surface, and conversely, the deformation on the tread surface is grooved. Since it can be made smaller than the bottom, slippage on the tread surface can be suppressed, and thereby uneven wear on the tread surface can be effectively prevented during the entire running process.
[0014]
Therefore, the tire of the present invention does not need to use many sipes as in the prior art, and even without using sipes, the braking and driving performance is ensured, and the occurrence of uneven wear in the groove portion of the river wear etc. Can be prevented.
[0015]
Further, in the tire according to the present invention, the zigzag of the corrugated wall surface A and the wall surface B along the tire circumferential direction has a groove width of the vertical groove from the respective apex sides a ₁ and b _{1 of the} tread surface toward the groove bottom. However, since the second slope of the wall surface B is further cut into the inner part of the land than the first slope, it is inclined in the direction of narrowing the drainage, that is, in the direction of reducing drainage. The second slope of the wall surface B also has an effect of preventing the drainage from being lowered in the longitudinal groove.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic tread development view showing an embodiment of a pneumatic tire according to the present invention. FIG. 2 is an enlarged schematic perspective view of a main part of the tire tread.
[0017]
1 is a tire tread, and 2 is a longitudinal groove extending linearly in the tire circumferential direction on the tread surface. Reference numeral 3 denotes a rib-like land portion continuously connected along the longitudinal groove 2.
[0018]
That is, in the tire according to the present embodiment, the rib-shaped land portion 3 includes the center rib 3c in the tire center area CA, the shoulder ribs 3a and 3e in the tire shoulder area SA, and the center rib 3c and the shoulder ribs 3a and 3e. It is comprised by each rib-like land part of mediate rib 3b, 3d of mediate area | region MA located in this. Between the shoulder rib 3a and the media rib 3b, between the media rib 3b and the center rib 3c, between the center rib 3c and the media rib 3d, and between the media rib 3d and the shoulder rib 3e. The vertical grooves 2a, 2b, 2c, and 2d are each linearly extended in the tire circumferential direction. In the figure, 4a and 4b are grounding ends, 9s is a sipe provided on the shoulder ribs 3a and 3e, 9m is a sipe provided on the mediate ribs 3b and 3d, 9c is a sipe provided on the center rib 3c, and TC is The tire equator line and CD indicate the tire circumferential direction.
[0019]
As shown in FIGS. 1 and 2, the tire according to the present embodiment is formed on the side wall portion 5 on the side of each vertical groove 2 in each land portion 3 from the tread surface 1 a toward the groove bottom 6. Zigzag is repeated on the side along the tire circumferential direction, and a corrugated portion 7 having a zigzag pitch length P of 3 to 8% of the tread width is provided. In the present invention, the tread width refers to the distance between the ground contact ends of the tread in the tire width direction. In the present embodiment, as shown in FIG. 1, the distance between the ground contact ends 4a and 4b corresponds to the tread width. Further, the zigzag pitch length P in the present invention is, for example, as shown in FIGS. 1 and 2, in a new tire, the zigzag protrusion 7a and the protrusion of the corrugated portion 7 appearing on the tire tread surface along the tire circumferential direction. Indicated by the distance between 7a.
[0020]
The shoulder rib 3a will be described in more detail as an example. The center rib 3c, the shoulder rib 3e, and the mediate ribs 3b and 3d also have the same corrugated structure as the shoulder rib 3a described in detail below.
[0021]
As shown in FIG. 2, the corrugated portion 7 of the shoulder rib 3a has apexes a ₁ , b located on both sides of the bent portion 8 recessed on the land portion 3 side (shoulder rib 3a side) on the tread surface 1a. ₁ has a wall surface A and a wall surface B which are inclined in the direction of narrowing the groove width of the longitudinal groove 2 toward the groove bottom 6.
[0022]
As shown in FIG. 2, the wall surface A includes a top side a _{1 of the} tread surface, a _first outer side a ₂ protruding toward the vertical groove 2, a bottom side a ₃ on the groove bottom side, and a land side of has one slope consisting of four sides of the inner side a ₄ of the bent portion.
[0023]
The wall surface B has the following first slope B ₁ and second slope B ₂ , and the first slope B ₁ is the first side common to the top side b ₁ of the tread surface 1 a and the slope A. Outer side a ₂ ,
And, the first outer side a ₂ is composed of three sides of the second outer side b ₂ connecting the intersection point IP intersecting the groove bottom and the bending point CP ₁ of the bent portion on the tread surface 1.
The second slope B ₂ includes the second outer side b ₂ , the inner side a _{4 of} the bent portion,
And, the outer side a ₂ groove bottom side of the bending point CP ₂ and the first of the inner side a ₄ is composed of three sides of the base b ₃ between the intersection IP intersecting the groove bottom.
[0024]
The tire of the present embodiment, the bending point CP ₂ of bent portions of the groove bottom side, wherein the first perimeter a ₂ along the groove bottom from the intersection IP intersecting the groove bottom to the top edge b ₁ It is located on the land side from the point C where the parallel straight line intersects the wall surface A. The dotted line shown in FIG. 2 shows a virtual line when only the first slope B ₁ is formed on the wall surface B without forming the second slope B ₂ , that is, the configuration of the slope of the conventional tire. Yes.
[0025]
In the tire according to this embodiment, the length of the top side a ₁ constituting the wall surface A is shorter than the length of the top side b ₁ constituting the wall surface B in an unworn new tire. Therefore, in the tire of this embodiment, a so-called multi-pitch zigzag pattern with a small pitch can be formed on the tread surface of an unworn new tire. On the other hand, as wear on the tread surface progresses, as shown in FIG. 3, the degree of zigzag appearing on the tread surface of the wall surface B, that is, the apex b ₁₁ after wear appearing on the first slope B ₁ and can be increased for the length of the new zigzag elements composed of the top side b ₄₁ after wear where appearing in the second inclined surface B _2. Therefore, as shown in FIG. 3, the tire of this embodiment after wear becomes a zigzag composed of the apex side a ₁₁ of the wall surface A, the apex side b ₁₁ and the apex side b _{41 of the} wall surface B, and the tire circumferential direction. In other words, the waveform portion 7 is formed by repeating two edges, that is, a first edge E ₁ and a second edge E ₂ .
[0026]
Since the tire of this embodiment is as described above, as shown in FIG. 2, the braking performance and the driving performance are exhibited on the tread surface when new or at the beginning of wear, and at the same time, the zigzag of the corrugated portion 7 is pitch length is zigzag so-called multi-pitch of 3-8% of the tread width, moreover zigzag corrugations 7 appearing on the tread surface 3a is and its walls a, mainly a first slope B _1, especially of the wall surface B Therefore, the degree of zigzag is small. Therefore, the tire according to the present embodiment has a configuration in which the features of the straight vertical grooves 2a are used as much as possible on the tread surface in the initial stage of wear, and the side wall 5 on the vertical groove 2a side in the land portion 1 is used. The uneven wear that occurs can be effectively prevented.
[0027]
Moreover, in the tire according to the present embodiment, as the wear progresses, the zigzag of the corrugated portion 7 is further added to the second slope B of the wall surface B in addition to the wall surface A and the first slope B ₁ constituting the wall surface B. ₂ appears, also, with the progress of wear of the tread surface, in addition to the configured edge E ₁ in the first inclined surface B ₁ of the wall surface a and wall B, the first inclined surface B ₁ and the second inclined surface B of the wall surface B And the second edge E ₂ composed of ₂ and ₂ gradually appear, and the intersection CP _{2 of} the inner side a _{4 with} the groove bottom is parallel to the apex b ₁ and passes through the point IP, and the wall surface A Since it is on the land side from the intersection C, the zigzag appearing on the worn surface becomes larger. Therefore, at the last stage of wear, the zigzag degree of the corrugated portion 7 constituted by the wall surface A and the first slope B ₁ and the second slope B ₂ of the wall surface B is set to be repeated in a maximum or near maximum state. can do.
[0028]
The tire of the present embodiment, the more we progress wear, the second occurrence state of slope B ₂ of the wall surface B, and a structure in which the braking performance and driving performance is cumulative increase, due to wear of the tread surface 1a with Throughout the entire process, traction, that is, a decrease in braking performance and driving performance can be suppressed and the same performance can be maintained.
[0029]
The above-described effects have been described by taking the shoulder rib 3a as an example, but the same applies to the corrugated portions constituting the groove walls of the center rib 3c, the shoulder rib 3e, and the mediate ribs 3b and 3d.
[0030]
FIG. 4 is a schematic tread development view showing another embodiment of the present invention. As shown in FIG. 4, the tire according to the embodiment includes a center block 10b corresponding to a land portion 10 extending intermittently in the tire circumferential direction in each of the tire center area CA and the mediate area MA on the tread surface, Eight blocks 10a and 10c are arranged. Further, shoulder ribs 11a and 11b corresponding to land portions 11 extending continuously in the tire circumferential direction are arranged in the tire shoulder region SA of the tread surface.
[0031]
12 is a tire tread, and 13 is a longitudinal groove extending linearly in the tire circumferential direction on the tread surface. Reference numeral 18 denotes a shallow lateral groove that opens from the land portion 10 in the tire center region and the mediate region to the adjacent longitudinal groove 13. By this lateral groove 18, a block-like land portion 10 is formed that is intermittently disposed in the tire circumferential direction in the tire center region and the mediate region. 9s is a sipe provided in the shawl Darli 11a and 11b, 9m is a sipe provided in the mediate blocks 10a and 10c, 9c is a sipe provided in the center block 10b, and 14a and 14b are grounding ends of the tire tread 12, respectively.
[0032]
Similarly to the tire of the above-described embodiment, the tire of this embodiment also has the vertical direction from the tread surface 12a toward the groove bottom 16 toward the side walls 15a and 15h on the longitudinal grooves 13a and 13d of the shoulder ribs 11a and 11b. Zigzag is repeated along the tire circumferential direction on the grooves 13a and 13d side, and a corrugated portion 17 having a zigzag pitch length P of 3 to 8% of the tread width is provided. The tread width refers to the distance between the ground contact ends 14a and 14b in the tire width direction of the tire tread 12 as in the above embodiment. The pitch length P is also defined in the same manner as in the above embodiment. The zigzag configuration of the corrugated portions of the shoulder ribs 11a and 11b is the same as in the above embodiment.
[0033]
The tire of the present embodiment is also applied to the center block 10b and the side wall portions 15b, 15c, 15d, 15e, 15f, and 15g on the side of the longitudinal grooves 13a, 13b, 13c, and 13d of the land portions 10 of the mediate blocks 10a and 10c. Corrugated portions 17b, 17c, 17d, 17e, 17f, and 17g having the same configuration as the corrugated portions 17a and 17h of the shoulder ribs 11a and 11b are provided.
[0034]
That is, the corrugated portions 17b, 17c, 17d, 17e, 17f, and 17g of the center block 10b and the mediate blocks 10a and 10c are respectively located on both sides of the bent portion that is recessed toward the land portion on the tread surface 12a. A wall surface A and a wall surface B that are inclined in a direction of narrowing the groove width of the vertical groove from the top side toward the groove bottom,
The wall surface A is composed of four sides: a top side of the tread surface, a first outer side protruding toward the longitudinal groove side, a bottom side on the groove bottom side, and an inner side of the bent portion on the land side. One slope,
Wall B has the following first and second slopes,
The first slope is the top side of the tread surface, the first outer side in common with the slope A,
And, the first outer side is composed of three sides of the second outer side connecting between the intersection point where the first outer side intersects the groove bottom and the bending point of the bent portion on the tread surface,
The second slope is the three sides of the second outer side, the inner side of the bent portion, and the base between the bending point on the groove bottom side of the inner side and the intersection of the first outer side. Configured,
The bending point of the bent portion on the groove bottom side is more than the point C where the straight line parallel to the top side of the first slope of the wall surface B crosses the wall surface A along the groove bottom from the intersection point IP of the first outer side. Located on the land side.
Note that TC indicates a tire equator line, and CD indicates a tire circumferential direction.
[0035]
Therefore, the tire of this embodiment also has the same effects as the tire of the above embodiment with the shoulder ribs 11a and 11b, the center block 10b, and the mediate blocks 10a and 10c.
[0036]
【Example】
A tire of the above embodiment having a tire size of 11R22.514PR having the tread pattern shown in FIGS. In the tire of Example 1, the width of the longitudinal grooves 2a and 2d is 12 mm, the width of the longitudinal grooves 2b and 2c is 14.5 mm, the zigzag pitch length P is 8.9 mm, and the top side a ₁ of the tread surface of the wall surface A ₁ and 2.2mm and the distance from the straight line connecting the vertex 7a and 7a of zigzag to CP _1, i.e. the depth of the zigzag in the tread surface and 2 mm, also connecting the vertices 7b and 7b of in zigzag groove bottom Each side and each slope are configured with the distance from the straight line to CP ₂ , that is, the zigzag depth at the groove bottom, being 4 mm.
[0037]
For comparison, a tire having the same tire size as that of Example 1 but having a configuration different from that of FIG. The principal part expansion schematic perspective view of the periphery of the vertical groove wall side surface of the tire of Comparative Example 1 is as shown in FIG.
The tire of Comparative Example 1 has two wall surfaces of a wall surface F and a wall surface G within one pitch, the pitch length P of the zigzag is the same as that of Example 1, and the top side a _{10 on} the tread surface, The lengths of the top side b ₁₀ and the zigzag depth on the tread surface are the same as in the first embodiment, and the wall surfaces F and G are configured so that the zigzag depth at the groove bottom is the same as the tread surface. Specifically, the length of the top side a ₁₀ on the tread surface is the top side a ₁ on the tread surface of Example 1, and the length of the top side b ₁₀ on the tread surface is the length of the tread surface of Example 1. in the top section b ₁ and the same dimensions, with depth of zigzag also the same as in example 1, with the top side a ₁₀ of a length of the top side portion corresponding a ₁₁₀ zigzag at the groove bottom is the tread surface, the groove The length of the zigzag top side corresponding part b ₁₁₀ at the bottom is the same as that of the top side b ₁₀ at the tread surface, the zigzag depth is the same as the tread surface, and the groove width extends from the tread surface to the groove. Walls F and G have the same width to the bottom and are arranged perpendicular to the tread surface.
[0038]
The pneumatic tires of these examples and comparative examples were used in a vehicle with a total weight of 19.5 tons. D. 2. Attached to the driving wheel of a regular type truck, the slip resistance performance was evaluated on a wet road test course.
The air pressure of each tire was set to 750 KPa, and the slip distance until the vehicle stopped by applying lock braking while the vehicle in a fixed volume state was traveling at 40 km / h was measured.
In the evaluation, for each tire of the example and the comparative example, a tire with 75% of the tire worn on the tire tread part by buffing after the measurement at the new article and after the measurement at the new article was made.
The test results are shown in Table 1. The test results are shown in the following formula, with the result when the comparative tire is new as 100. The larger the value, the better the performance.
Anti-slip performance index K = [((Slip distance of tire of comparative example when new)) / (Slip distance of each tire)] × 100
[0039]
[Table 1]

[0040]
As can be seen from Table 1, the tire of the present invention is superior in slip resistance performance at both the 50% wear point and the 75% wear point as compared with the conventional comparative tire.
[0041]
【The invention's effect】
Since the present invention is as described above, in a pneumatic tire having a longitudinal groove extending linearly in the tire circumferential direction, braking performance from the initial stage of wear to the end stage without much use or use of sipes on the tread surface. In addition, it is possible to maintain drive performance and prevent uneven wear that occurs on the surface of the land portion on the longitudinal groove side.
[Brief description of the drawings]
FIG. 1 is a schematic tread development view showing an embodiment of a pneumatic tire according to the present invention.
FIG. 2 is an enlarged schematic perspective view of a main part of the tire.
FIG. 3 is an enlarged schematic perspective view of a main part showing a state of a worn tread surface in the tire.
FIG. 4 is a schematic tread development view showing another embodiment of the pneumatic tire according to the present invention.
FIG. 5 is an enlarged schematic perspective view of a main part of a pneumatic tire according to a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tire tread 1a Tread surface 2 Longitudinal groove 3 Land part 4a Grounding end 4b Grounding end TC Tire equatorial line CD Tire circumferential direction P Zigzag pitch length 5 Side wall part 6 Groove bottom 7 Waveform part 8 Bending part a ₁ Top side a ₂ first outer side _{a 3} base _{a 4} in side a wall B wall _{B 1} first inclined surface _{B 2} second slope _{b 1} top side b ₂ second perimeter _{b 3} base IP intersections CP ₁ bending point CP ₂ bend point DESCRIPTION OF SYMBOLS 10 Land part 11 Land part 12 Tire tread 15 Side wall part 16 Groove bottom 17 Corrugated part F Wall surface G Wall surface

Claims (2)

The tire tread surface is intermittently arranged by a plurality of vertical grooves extending linearly in the tire circumferential direction, and a rib-like land portion continuously connected along the vertical grooves or a plurality of horizontal grooves along the vertical grooves. In a pneumatic tire having a block-shaped land portion,
The zigzag is repeated along the tire circumferential direction from the tread surface toward the groove bottom direction along the tire circumferential direction on the side wall portion on the vertical groove side in the land portion, and the pitch length of the zigzag is 3 to 8% of the tread width. Is provided with a waveform section,
The corrugated portion is inclined in the direction of narrowing the groove width of the vertical groove from the apexes a ₁ and b ₁ located on both sides of the bent portion recessed toward the land portion on the tread surface. Wall surface A and wall surface B
Wall A is
The top side a _{1 of the} tread surface;
A first outer side a ₂ protruding to the longitudinal groove side;
The bottom side a ₃ on the groove bottom side;
Inner side a _{4 of the} bent portion on the land side
One slope composed of four sides,
The wall surface B has the following first slope B ₁ and second slope B ₂ ,
The first slope _{B 1} is,
The top side b _{1 of the} tread surface,
The first outer side a ₂ in common with the slope A;
And, the second outer side b ₂ connecting the intersection point IP where the first outer side a ₂ intersects the groove bottom and the bending point CP ₁ of the bent portion on the tread surface.
It consists of three sides
The second slope _{B 2} is,
The second outer side b ₂ ,
The inner side a _{4 of} the bent portion,
And the bottom side b ₃ between the bend point CP ₂ on the groove bottom side of the inner side a ₄ and the intersection point IP at which the first outer side a ₂ crosses the groove bottom.
It consists of three sides
Bending point CP ₂ of bent portions of the groove bottom side, wherein the first perimeter a ₂ is parallel to the top edge b ₁ along the groove bottom from the intersection IP crossing the groove bottom straight line that intersects the wall surface A A pneumatic tire characterized by being located on the land side of C. The pneumatic tire according to claim _{1, wherein} the length of the apex side a ₁ constituting the wall surface A is shorter than the length of the apex side b ₁ constituting the wall surface B.

Images